c++ - Text Clipping with Qt OpenGL -

i'm working qt5.1 , trying draw opengl stuff within qglwidget:

void widget::paintgl() {     startclipping(10, height()-110,100,100);      qglcolor(qt::red);     glbegin(gl_quads);         glvertex2d(0,0);         glvertex2d(500,0);         glvertex2d(500,500);         glvertex2d(0,500);     glend();      qglcolor(qt::green);     this->rendertext(50, 50, "scissor test string");      endclipping(); } 

the quad gets clipped correctly text doesn't. tried 3 ways of implementing startclipping method: scissor test, setting viewport clipping area , stencil buffer. none of them worked , whole string drawn instead of beeing cut off @ edges of clipping area.

now question is: behavior bug of qt or there something, missed or possibility try??

after week of trying around, found simple way achieve, looking for. using qpainter , it's methods instead of qglwidget's rendertext() makes text clipping work:

qpainter *painter = new qpainter(); painter->begin();  painter->setclipping(true);  painter->setclippath(...);   // or painter->setcliprect(...);   // or painter->setclipregion(...);  painter->drawtext(...);  painter->end();